Soumya I, Rahman M Zia Ur, Reddy D V Rama Koti, Lay-Ekuakille A
Department of E.I.E, GITAM University, Visakhapatnam, India.
Department of E.C.E, K.L. University, Vaddeswaram, Green Fields, Guntur, Andhra Pradesh, India.
Rev Sci Instrum. 2015 Mar;86(3):035003. doi: 10.1063/1.4913658.
In real time clinical environment, the brain signals which doctor need to analyze are usually very long. Such a scenario can be made simple by partitioning the input signal into several blocks and applying signal conditioning. This paper presents various block based adaptive filter structures for obtaining high resolution electroencephalogram (EEG) signals, which estimate the deterministic components of the EEG signal by removing noise. To process these long duration signals, we propose Time domain Block Least Mean Square (TDBLMS) algorithm for brain signal enhancement. In order to improve filtering capability, we introduce normalization in the weight update recursion of TDBLMS, which results TD-B-normalized-least mean square (LMS). To increase accuracy and resolution in the proposed noise cancelers, we implement the time domain cancelers in frequency domain which results frequency domain TDBLMS and FD-B-Normalized-LMS. Finally, we have applied these algorithms on real EEG signals obtained from human using Emotive Epoc EEG recorder and compared their performance with the conventional LMS algorithm. The results show that the performance of the block based algorithms is superior to the LMS counter-parts in terms of signal to noise ratio, convergence rate, excess mean square error, misadjustment, and coherence.
在实时临床环境中,医生需要分析的脑信号通常非常长。通过将输入信号划分为几个块并进行信号调理,可以简化这种情况。本文提出了各种基于块的自适应滤波器结构,用于获取高分辨率脑电图(EEG)信号,这些结构通过去除噪声来估计EEG信号的确定性成分。为了处理这些长时间信号,我们提出了用于脑信号增强的时域块最小均方(TDBLMS)算法。为了提高滤波能力,我们在TDBLMS的权重更新递归中引入归一化,这产生了TD - B - 归一化最小均方(LMS)。为了在所提出的噪声消除器中提高精度和分辨率,我们在频域中实现时域消除器,这产生了频域TDBLMS和FD - B - 归一化LMS。最后,我们将这些算法应用于使用Emotive Epoc EEG记录器从人体获得的真实EEG信号,并将它们的性能与传统LMS算法进行比较。结果表明,基于块的算法在信噪比、收敛速度、超额均方误差、失调和相干性方面的性能优于LMS对应算法。